Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

I am white when I am dirty, and black when I am clean. What am I?

What do you get if you add 2 to 100 four times?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?